Cardiovascular Disorders II Flashcards
Coronary Artery Disease (CAD)
aka Coronary Heart Disease (CHD) or Ischemic Heart Disease (IHD)
2nd leading cause of death in Canada
1 in 12 Canadian adults live with diagnosed heart disease
Left Main Coronary Artery (LMCA)
left side of heart muscle 2 branches a. left anterior descending (interventricular) - front and left side of heart b. circumflex - outer side and back of heart
Right Coronary Artery (RCA)
right side of heart muscle
right ventricle and atrium, SA and AV nodes
Pathophysiology of CAD
- decreased perfusion to myocardium due to occlusion of 1+ coronary arteries or branches
- inadequate blood supply to meet the myocardial oxygen demand
- myocardial ischemia
- myocardial death
Atherosclerosis
++ blood levels of lipids irritate or damage intima of arterial vessels
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fatty substances enter vessels after damaging the protective barrier, accumulate and form fatty streak
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smooth muscle cels move to intima to engulf fatty substance
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fibrous tissue formation and calcification
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atheroma grows, vessel wall becomes thick, fibrotic and calcified, lumen narrows
* impedes blood flow with risk for thrombosis
Collateral Circulation
with gradual occlusion of the larger vessels, the smaller collateral vessels increase in size and provide alternative channels for blood flow
CAD Risk Factors
Non-modifiable
a. age
b. sex (women, men have slightly higher risk at younger age)
c. family history (familial hypercholesterolemia, mutation on gene LDL receptors
Modifiable
a. serum lipid alterations (decreased HDL and increased LDL and triglycerides)
b. hypertension
c. smoking
d. diabetes mellitus (insulin resistance)
- endothelial damage
e. diet
f. obesity (lipid metabolism)
g. lack of physical activity
Cholesterol
serum lipid abnormality is responsible for atherogenesis
- it is what creates plaque
high triglyceride level with high HDL or low HDL increases risk for atherosclerosis
= lipid synthesized by the liver or ingested
= required for synthesis of certain hormones and bile salts
= insoluble in water, requires lipoprotein for transportation
Lipoproteins relevant to CAD
Very-low-density lipoproteins (VLDL)
- produced by liver and converted in blood stream to LDLs
- for delivery of TRIGLYCERIDES to non-hepatic tissue
Low-density lipoproteins (LDL)
- produced in liver as VLDL
- for delivery of mainly CHOLESTEROL to non-hepatic tissue
High-density lipoproteins (HDL)
- produced in liver and small intestine
- reverse cholesterol transport, helps to EXTRACT EXCESS CHOLESTEROL deposited in blood vessels back to liver for elimination
- antioxidant and anti-inflammatory functions
Metabolic Syndrome
specific risk factors markedly increase potential for heart disease
3 out of 5 conditions:
a. Waist circumference
Men > 102cm
Women > 88cm
b. Triglyceride levels
> 1.7 mmol/L
c. HDL cholesterol
Men < 1 mmol/L
Women < 1.3 mmol/L
d. BP
SBP > 130 mmHg
DBP > 85 mmHg
e. fasting glucose
> 5.6 mmol/L
Management of CAD
a. modify risk factors (control bp, diabetes, lifestyle, weight)
b. health promotion (identifying at risk, manage underlying condition)
c. nutrition therapy (complex carbohydrates, omega-3 fatty acids)
d. medications (cholesterol-lowering, anti-platelet agents)
Diagnostic tests of CAD
a. ECG detect myocardial ischemia b. Stress testing effects of exercise (stress) on heart c. Cardiac catheterization catheter through a peripheral artery into aorta and left heart under fluroscopic imaging d. Coronary angiography injection of contrast medium into coronary arteries to visualize lesions
Percutaneous Transluminal Coronary Angioplasty (PTCA)
blocked or narrowed portions of the artery are dilated with a catheter and inflated ballon to flatten plaque
may be followed by a mesh stent insertion to keep it open, may also prevent further plaque build up
Coronary Atherectomy
removal of plaques that form a blockage
- generally used BEFORE angioplasty balloon is inflated
- reduce blockage and force needed to inflate balloon
Coronary Bypass Grafting (CABG)
surgical intervention to bypass blockages between the aorta and the myocardium with grafting of vessels distal to the area of blockage